I would think that the F8 preamps would be better quality than those Triton FetHead's, but I've also never heard one of them. I do think that they're pretty neat little prreamps though, and they have 48v versions for condenser mics and a ribbon mic version, so that's pretty cool IMO! But I would just sit back and enjoy the internal preamps of the F8 if I were you and that's what you end up getting, unless they end up not being what you're looking for! I have really been enjoying running just Caps>KCY>60v PFA's>MixPre6 Preamps and leaving my huge Schoeps VMS02IB Preamp at home lately
Also, for the same price, you can get a new Sound Devices MixPre6 haha
But if you're already set on an F8, then I say go for it! The F8 does have some really clean gain, although it's a little bit bright for my tastes sometimes! Is there anyway that you can borrow/rent one for a few days and try it out before you buy one? If so, I'd go that route. Maybe a retailer somewhere nearby you has one or something like that? Maybe another taper lives close by that has an F8? I just bought a new MixPre6 blindly before using one a couple of months ago, and I couldn't be any happier! So if you're craving a nice, new, minty F8, then like I just said, I would go for it
We only live once!
That said, I don't recall ever hearing a ribbon mic>F8, so I don't know where there would be any samples of that particular combo? I hope that everything works out for you and you find the right deck for those ribbons, and Happy Taping